The Chinese hacker group that broke into the computer network of The New York Times and other high-profile organizations, including defense contractors, has launched new attacks following a few months of inactivity, according to researchers from security vendor FireEye.

The cyberespionage group is known as APT 12 (Advanced Persistent Threat number 12) and is believed to have ties to China's People's Liberation Army (PLA).

APT 12 is back after a period of silence following widespread media coverage in January of The New York Times security breach and reports revealing the group's methods and operations, FireEye researchers said Monday in a blog post.

"We observed new activity from this group in early May 2013," said Ned Moran, senior malware researcher at FireEye, via email. "We are almost certain that these new attacks were conducted by the same group."

The attacks used new variants of Backdoor.APT.Aumlib and Backdoor.APT.Ixeshe, malware programs previously associated with APT 12, as well as command and control infrastructure attributed to the group, Moran said.

The new Aumlib version was used to target an organization that helps shape international finance and economic policy, while the new Ixeshe variant was used in attacks against entities in Taiwan, according to the FireEye researchers. The targeted organizations were not named.

The APT 12 group made changes to the network communication protocols in its malware tools so that the traffic patterns they generate differ from those of older versions.

This was done in order to evade detection by intrusion detection systems, Moran said. The FireEye blog post includes details about the traffic changes that will help companies create new signatures for their detection tools, he said.

It's possible that there are ongoing attacks using these updated Aumlib and Ixeshe versions, Moran said. "We recommend that companies ensure that their detection tools are able to identify these new variants."

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